enum
{
    OFF,
    ON,
    min_vol = 0,
    max_vol = 100,
    min_channel = 0,
    max_channel = 100
};
class TV
{
    friend class Remote;

private:
    int state;
    int vol;
    int channel;

public:
    TV(/* args */)
    {
        state = OFF;
        vol = min_vol;
        channel = min_channel;
    };
};

class Remote
{

private:
    TV *tv;

public:
    Remote(TV *p)
    {
        tv = p;
    }
    void turn_on_TV();
    void turn_off_TV();
    void increase_vol();
    void vol_down();
    void add_channel();
    void sub_channel();
    void show_TV();
};